Adjustable beam lamp



. y 1970 J. A. MUSCOVITCH 3,511,985

ADJUSTABLE BEAM LAMP 3 Sheets-Sheet 1 Filed June 8, 1967 INVENTOR.JOSEPH A. MUSCOVITCH M y 1 1970 J; A. MUSCOVITCH 3,511,985

ADJUSTABLE BEAM LAMP Filed June 8, 1967 INVENTOR. JOSEPH AMUSCOVITCHATTORNEY ,May 12, 1970 J. A. MUSCOVITCH ADJUSTABLE BEAM LAMP 3Sheets-Sheet 5 Filed June 8, 1967 FIG.5

FIG-3.6

INVENTOR. JOSEPH A. MUSCOVITCH BY ATTORNEY PIC United States Patent O3,511,985 ADJUSTABLE BEAM LAMP Joseph A. Muscovitch, 37 Franklin Ave.,

- Saddle Brook, NJ. 07662 Filed June 8, 1967, Ser. No. 644,590 Int. Cl.F21v 7/06 US. Cl. 24044.1 8 Claims ABSTRACT OF THE DISCLOSURE Anadjustable beam lamp having a reflector capable of reflecting aconcentrated beam when the light source is located at the focal centerthereof and having a light bulb socket and reflector housing mounted formovement relative to each other for positioning the bulb filament at thefocal point of the reflector. The reflector is movably mounted withinthe housing for manual adjustment of the reflector in a position inwhich its center is located behind the light bulb for producing anintense concentrated beam of reflected light, and selective positions inwhich curved surfaces of the reflector of lesser diameter are locatedbehind the bulb for producing dispersed beams of variable andcontrollable spread.

BACKGROUND OF THE INVENTION In many applications, it is desirable toprovide a concentrated beam of intense light for illuminating a smallarea. In machine shop work, for example, where direct light on layout iscritical, a bench lamp capable of producing an intense spot is often anecessity. It is usually impractical to provide such spot illuminationby bringing an ordinary lamp close to the work, since the lampinterferes with the workers movement, and often gets spattered with oilor the like. It is also desirable to adjust the beam of light to produceilluminated spots of varying areas.

Focussing lamps which will vary the area of light beams are presentlyavailable as hospital and dental operating lights, for example. Theselamps operate on the principle of varying the spacing between the lightbulb and the reflector to provide a limited control over the spot.However, when the spacing between the bulb and reflector is increased, ahalo effect is produced, so that the lamps include a Fresnel lensforwardly of the bulb to eliminate this halo effect. The provision ofsuch lens system as well as means for adjusting the bulb position,increases the cost of the lamp to such anextent as to render itimpractical for shop use.

Accordingly, an object of this invention is to provide a lamp capable ofproducing a concentrated spot of light for intense illumination of asmall area, and variable by adjustment to produce gradually increasingareas of more diffused illumination.

Another object of the present invention is to provide a lamp of thecharacter described in which a variable area light beam is attainedwithout the use of a lens or lens system. I

Still another object of the invention is to provide a lamp having meansfor adjusting the bulb and reflector relative to each other in such amanner that the bulb filament may be located at the focal center of thereflector for producing a concentrated beam of parallel rays.

A further object of the present invention is to provide a lamp of thetype described which is simple in construction, economical inmanufacture, and reliable in operation.

In accordance with the invention herein, there is provided a lampincluding a socket for mounting a light bulb and a reflector locatedbehind the light bulb. The reflector is of such type, for example theparabolic type, as to reflect the light emitted by the bulb in parallelrays so as to provide a concentrated beam when the bulb filament islocated at the focal center of the reflector. The reflector is mountedwithin a housing which is movable relative to the light bulb forlocating the bulb filament at the focal center of the reflector. Thebulb socket is also movably mounted for proper positioning of the bulbrelative to the reflector to accommodate bulbs of different sizes. Thereflector is also movably mounted within the housing for adjusting thereflected light variably between a concentrated beam and a diffusedbeam.

Other objects and advantages of the present invention will becomeapparent from a consideration of the following detailed description whentaken in conjunction with the accompanying drawings, in which:

, FIG. 1 is a perspective view of a lamp constructed in accordance withthe present invention;

FIG. 2 is a central vertical section of the lamp shown in FIG. 1, withthe inoperative position of the socket being shown in broken line;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a perspective view of the heat shield forming part of the lampassembly; and

FIGS. 5-7 are diagrammatic illustrations of the light patterns producedby the lamp of the present invention for various positions of thereflector relative to the source of light.

Referring now to the drawings and in particular to FIG. 1, there isshown a lamp constructed in accordance with the present invention anddesignated generally by the reference numeral 10. The lamp includes aconventional threaded socket 12 which is adapted to receive therein asource of light such as a light bulb 14 having a filament 15. Dependingfrom the bottom surface of the socket 12 is a centrally located swivelmember 16 which is received between the spaced ears of a bifurcatedsocket supporting member 18 (FIGS. 2 and 3). A screw 20, extendingbetween the ears of member '18 and through member 16, provides a swiveljoint pivotally mounting the socket 12 on the connecting member 18.Thus, the socket is movable between an operative position shown in solidline in FIG. .2, and an inoperative position shown in phantom, thedirection of movement being indicated by the arrow 22. It .will beunderstood that other conventional types of swivel means may be employedinstead of screw 20 to permit movement of socket 12.

The socket supporting member 18 has an externallythreaded lower tubularsection 24, as shown in FIG. 2. The lower end of the tubular section 24may be connected with a conventional mechanical swivel arm or support(not shown) so that the lamp 10 may be set inany desired positionrelative to a base or clamp supporting the mechanical swivel arm. Forenergization of the bulb 14, the socket 12 may be connected in theconventional manner to a pair of wires (not shown) which extend throughthe tubular section 24 and the swivel arm section of the lamp to connectthe socket 12 and the inserted light bulb 14 with a source of potentialthrough the usual on-oif switch. I

Adjustably mounted on the tubular section 24 of the connecting member 18is a reflector housing designated generally by the reference numeral,26. The reflector housing 26 includes a concave hemisphericalbodyportion 28 having a bottom opening 30 which extends to one edgethereof and is sized to receive the socket 12 therein,

3 bular section 24 of the socket supporting member 18. A lock nut 36(FIG. 2) or similar clamping device is mounted on the tubular section 24and is adapted to abut the sleeve 34 to maintain the reflector housing26 at a predetermined height relative to the light bulb 14.

As shown in FIGS. 2 and 3, the hollow bracket 32 is sufficiently wide toreceive the socket supporting member 18 and a portion of the socket 12therein, and the communicating opening 30 in housing body portion 28 isalso sized to receive the socket therein. Thus, the socket 12 may bepivoted rearwardly to move the light bulb 14 toward the reflectorhousing and well within the confines thereof. In addition, 'by rotatingthe reflector housing 26 upon the threaded tubular section of the socketsupporting member 18, the housing 26 is moved longitudinally along saidthreaded section and is thus raised or lowered relative to the socket 12and its contained light bulb 14. In this manner, the light bulb,regardless of size, may be properly positioned within the reflectorhousing, as will be presently explained. The lock nut 36 may then beturned into tight frictional engagement with the sleeve 34 to retain thereflector housing in the set position.

Received within the hemispherical body portion 28 of the reflectorhousing 26, for sliding movement with respect thereto, is a highlypolished or mirrored concave reflector 40. More specifically, thereflector housing 26 is provided with a pair of opposed guide memberswhich permit this sliding movement of the reflector 40. Each guidemember comprises a screw shank 44 aifixed to the inner surface of thehousing 26, and a circular nut 42 threadedly mounted on the screw shank.The nut 42 is formed with one or more legs which act as spacer elementsto position the nut a selected distance from the inner surface of thereflector housing body portion 28. Punched out lugs from the reflectorhousing may be employed instead of the screw shanks 44 and nuts 42.

In assembling the lamp, t-he reflector 40 is inserted within the housing26 between the screw shanks 44, and the nuts 42 are threaded upon therespective screw shanks until the spacer legs engage the inner surfaceof housing 26. The nuts 42 prevent movement of the reflector 40outwardly and away from the housing 26, but permit turning movement ofthe reflector 40 along the inner surface of the housing.

Secured to the reflector 40, adjacent the upper edge thereof, is anupstanding post 46 which extends through an elongated slot 48 in the topof the concave body portion 28 of the reflector housing 26. The slot 48,as shown in FIG. 1, extends downwardly over a portion of thecircumference of the housing body portion 28. The upper end of the post46 is threaded for mounting an internallythreaded clamping member 50thereon. The bottom surface of the member 50 is adapted to be screwedinto tight frictional engagement with the outer surface of housing bodyportion 28 to maintain the reflector 40 in a preselected adjustedposition relative to the filament in the light bulb 14. In use, theclamping member 50 may be loosened and grasped to move the post 46within the slot 48, such movement adjusting the position of thereflector 40 with respect to the bulb filament 15. The reflector 40turns within the housing 26, guided by the engagement of nuts 44 withthe edge of the reflector.

The lamp 10 also includes a supplementary reflector or heat shield shownin FIG. 4 and designated generally by reference numeral 52. Thesupplementary reflector 52 includes a circular, concave reflecting plate54 mounted on a pair of forwardly-extending arms 56 which are formedintegrally with a transverse connecting member 58. The connecting memberis in turn secured at its center to the top of a depending leg 60, tothe bottom of which is secured a split ring 62. The split ring 62 isflexible, being formed of a strip of resilient metal such as springsteel, and being sized to be snapped around socket 12 and frictionallyretained in mounted position, in the manner shown in FIGS. l-3. The leg60 is of such size that the ring 62 may be positioned on socket 12 so asto locate the concave reflecting plate flush against the outer surfaceof the light bulb 14 and centered upon the filament 15 of said bulb. Theleg 60 is also flexible to permit swivel movement of the supplementaryreflector 52 so that the latter will align itself in flush abutment withthe light bulb. As an alternative, the connecting member 58 may beswivelly 'mounted on leg 60. The reflecting plate 54 is of suflicientlylarge diameter to reflect substantially all of the forwardly-emittedrays of the bulb 14 in its area back to the reflector 40.

In practice, the reflector 40 is a parabolic reflector having aprincipal axis extending through the center of the reflector andindicated by the broken line 64 in FIG. 2. Located on the principal axis64 is the focal point F of the reflector. It will be apparent that whenthe reflector 40 is located behind the bulb in an adjusted position inwhich the bulb is in registry with the central reflecting surface of thereflector, and with the bulb filament 15 located on the principal axis64 at the focal point F, a concentrated beam of light will be produced.As the reflector 40 is turned within the housing 26 from this adjustedposition, the distance between the bulb filament 15 and the focal pointF will change solely because of the curvature of the reflector, and areflecting surface of lesser diameter than the central surface of thereflector will move in registry with the bulb, thereby presenting acurved reflector surface area rather than a parabolic surface, andproducing a wider, more diffused beam, as described in detailhereinbelow. It will be understood that while a parabolic reflector ispreferred, the invention contemplates the use of other types ofreflectors having varying surfaces which may be brought selectively intoregistry with the lamp bulb in order to obtain a concentrated spot aswell as various light dispersion patterns. For example, the sideportions of the parabolic reflector can be cut away to provide an oblongreflector to enable a smaller lamp unit to be made for portable use byauto mechanics, machine repair operators, and the like.

For insertion of a light bulb into the lamp, the socket 12 is turnedabout pivot 20 in the direction of the arrow 22 to the inoperativeposition shown in broken line in FIG. 2. The light bulb 14 is thenscrewed within the socket 12 in the usual manner so that proper contactwith the socket terminals is made, and the socket 12 is then pivoted tothe upstanding operative position shown in full line in FIG. 2. As willbe presently explained, in establishing the operative position, thesocket 12 is pivoted until the bulb filament 15 coincides as closely aspossible with the focal point F of the reflector 40. It is to beunderstood that the term bulb filament is intended to include any lightsource in a bulb, such as horizontal, vertical, V-shaped, orpre-focussed wire filaments, as well as incandescent beads or gas spots.

In order to further adjust the lamp for positioning the bulb at thefocal center of the reflector, the reflector housing 26 may be rotatedrelative to the socket supporting member 18, the sleeve 34 turning uponthe threaded section 24 to raise or lower the bulb 14 relative to thereflector 40, so that the bulb may be positioned centrally within saidreflector. In addition, in order to obtain the greatest efiiciency ofthe light bulb 14, it is highly desirable that the filament 15 beoriented in a plane perpendicular to the principal axis 64 of therefiector. Accordingly, after the bulb has been screwed into the socket12, the reflector housing 26 may be turned until a position is reachedin which the bulb filament 15 extends transversely to the principal axisof the reflector. Such a position is shown in FIG. 1.

It is to be understood that for obtaining an optimum concentration oflight, the light bulb 14 should be of the clear glass type rather thanof the frosted type. A frosted bulb will emit a diffused beam lightpattern which will not be properly reflected to provided a concentratedspot.

After the light bulb 14 has been properly located in adjusted positionas described above, the angular position of the reflector 40 may beadjusted. For this purpose, the clamping member 50 is loosened and thepost 46 slid through slot 48 until the principle axis 64 of thereflector passes through the filament 15 and the focal point F coincideswith the filament. This position can be determined by visual observationof the spot of light reflected by the lamp. Clamping member 50 is thentightened to retain the reflector 40 in adjusted position.

Reference may now be had to the schematic views of FIGS. 5 and 6 for amore detailed explanation of the operation of the present invention.Initially, it will be assumed that the supplementary reflector 52 is notutilized. As shown in FIG. 5, when the filament 15 (represented by acircle for purposes of illustration) is positioned at the focal point Fof the reflector 40, the rays of light emitted radially from thefilament 15 will strike the reflector 40 and will be reflected as raysparallel to the principal axis 64 to produce a spot of light 66 having aminimum area. In other words, when the source of light is positioned onthe focal point of the parabolic reflector 40, the reflected rays oflight will be parallel so as to produce the circular spot 66 of maximumconcentration.

When it is desired to increase the area illuminated by the lamp, theclamping member 50 is loosened and moved to a selected position relativeto the reflector housing 28, as indicated by the arrow 67 in FIG. 2,causing corresponding turning movement of the reflector 40 Within saidhousing. More specifically, as the post 46 is moved through the slot 48,the positions of the focal point F and of the principal axis 64 ofreflector 40 will shift with respect to the source of light 15. Thereflector is turned Within the housing until its central reflectingsurface is out of registry with the rear of bulb filament 15 and anoffset selected surface thereof is located behind and in registry withthe bulb filament, as indicated in FIG. 6. In the position of FIG. 6,for example, the focal point F is located above and to one side offilament 15 and a curved surface area of lesser diameter than the centerof the reflector is located behind the bulb to act as a curved mirroredreflector plate.

Due to the curvature of the parabolic reflector 40, it will now beobvious that not all the rays which are reflected by the reflector willbe parallel to each other. Most of the rays emitted by the filament 15will strike the surfaces of the reflector with varying angles ofincidence, resulting in diverging reflected rays and a wide spotindicated at 68 of FIG. 6. Accordingly, the area of the spot illuminatedby the light beam will be substantially greater than the areailluminated by the light beam when the source of light is positioned atthe focal point F of the reflector 40. Hence, simply by moving thereflector 40 relative to the source of light 15 by means of the clampingmember 50 and the post 46, the area which is illuminated by the lamp 10of the present invention may be selectively varied in accordance withthe dimensions of the object which is to be illuminated.

It is to be noted that as the area of the light beam is dispersed, theirradiance of the light will correspondingly decrease. Hence, not onlydoes the lamp 10 of the present invention provide a means for increasingthe area of a light beam from a minimum area, but it also produces alower density light, thereby decreasing the glare produced by the beam.

When the source of light is positioned at the focal point F of thereflector 40 it is to be noted that those rays of light which are notreflected (i.e. the rays which pass directly outwardly from the source15) will be at random angles with respect to the paraxial rays. In orderto eliminate these randomly oriented light beams and thereby increasethe irradiance of the lamp 10, the sup plementary reflector plate 54 maybe utilized, as shown in FIG. 7. The supplementary reflector 52 ispositioned so that the reflecting plate 54 is in front of and alignedwith the filament 15 of the light bulb 14. Accordingly, those rays suchas light rays 70 which are directed forwardly from the filament 15 willimpinge on the supplementary reflector plate 54 and will be reflectedback to the reflector 40. Thus, these rays will likewise be reflectedfrom the reflector 40 as rays which are parallel to the principal axisof the reflector thereby to increase the illumination produced by thelight beam and eliminate the fuzziness or fringe area which mayotherwise exist around the periphery of the area 66. The supplementaryreflector also acts as a shield to deflect direct heat radiation fromthe filament.

Accordingly, a lamp has been disclosed which produces a light beamhaving a variable area in accordance with the requirements of the user,which is simple in construction and reliable in operation.

While a preferred embodiment of the invention has been shown anddescribed herein it will be obvious that numerous omissions, changes andadditions may be made in such embodiment without departing from thespirit and scope of the present invention.

What is claimed is:

1. A lamp comprising socket means for mounting a light bulb having alight source, a reflector housing, means connecting said reflectorhousing with said socket means for positioning the light bulb centrallyand immovably within the reflector housing, a parabolic reflector havinga preselected focal point and an arcuate central reflecting surfaceshaped to reflect the light of said bulb in a con centrated beam ofparallel rays when the light source of the light bulb is located at saidfocal point, and mounting means movably mounting said reflector in saidhousing relative to said immovable light bulb for movement around saidlight bulb between a first position in which the central reflectingsurface is located behind and in registry with the bulb and said bulblight source coincides with the focal point of the reflector, andprovides a concentrated beam of light with parallel rays, and variablepositions in which said focal point is spaced from said bulb lightsource and portions of the reflector of varying curvatures dilferingfrom the curvature of said central reflecting surface are located behindand in registry with said bulb, to produce a wider and more diffusedbeam.

2.. A lamp according to claim 1, in which said mounting means mountssaid reflector for revolving movement within said housing about saidlight bulb.

3. A lamp according to claim 2, wherein said mounting means includesopposed, inwardly-directed guide members fixed upon the inner surface ofsaid reflector housing, said guide members being located to engagediametrically opposed edges of said reflector for sliding movement ofsaid edges therealong as said reflector is turned Within said housing.

4. A lamp according to claim 3, in which said mounting means includes anelongated slot in said reflector housing, a post fixed to said reflectorand extending through said elongated slot for turning movement of saidreflector within said housing when said post is selectively moved alongsaid slot, and clamping means received on the end of said post andadapted to frictionally engage said reflector housing to maintain saidreflector in adjusted position relative to said bulb light source.

5. A lamp according to claim 1, in which said connecting means includesa first threaded member connected to said lamp socket means, and asecond threaded member connected to said reflector housing and inthreaded engagement with said first threaded member, whereby relativemovement of said first and second threaded members causes movement ofsaid reflector housing relative to said lamp socket means and theinserted light bulb, and in a direction substantially longitudinal ofthe latter.

connecting said lamp socket means with said first threaded member forselective. movement of the bulb received in lamp socket means toward'andaway from the inner surface of said reflector.

7. A lamp according to claim'l, which also includes "a supplementaryreflector connected to said lamp socket means and positioned in-frontofsaid lightbulb to reflect forwardly-emitted rays from said bulb lightsource back "8 'A lamp according to claim 7, in which said supple-"mentary reflector includes a concave reflecting plate, and bracketmeans connected to said reflecting plate and engageable with said socketmeans to rernovably mount said supplementary reflector on said lampsocket means in a position in which said reflecting plate is in flushabutment with the front surface of said light bulb.

- I "UNITED 1,638,716 2,666,194

References Cited STATES PATENTS '8/1927 Surles 24010.69 XR 1/1954He6hl6r 24044.1 XR 7/1968 Neely et, 1. 240-84 XR 7/1922 Humiston 24010.69 8/1922 Wood 240-44.l 10/1922 Stimson 24()10.69 1/1924 OConnor'24044.1 6/1926 Reymond 24044.1 12/1934 Benford 24044 XR 2/1938 Bardwellet al. 240-44 FOREIGN PATENTS 12/1908 England.

NORTON ANSHER, Primary Examiner R. P. GREINER, Assistant Examiner

